Electrical connecter



June 11, 1935. I R E FARlsH, JR 2,004,105-

ELECTRICAL CONNECTER Filed Nov. 25, 1952 2 Sheets-Sheet 1 Z7 /l f l/ Elma/who@ June ll, 1935. R. E. PARISH, JR

I ELECTRICAL CONNECTERv Filed NOV. 23, 1932 2 Sheets-Sheet 2 W m w.

a as nu@ Patented June 1l, 1935 UNITED STATES PATENT OFFICE ELECTRICAL CONNECTER Robert E. Farah, Jr., Columbus, Ga.'

' Application November 23, 1932, Serial No. 644,097

ZCIaims.

This invention relates to improvements in electrical connecters and has particular reference to a connecter of the separable type such as used in making connections for lamps, heaters, irons 5 and other electrical appliances.

' In one type of separable connecter most universally used, the plug member is provided with two prong terminals which are insertable into corresponding openings formed in the socket member in order to establish an electrical circuit through the connecter. It is well known that difficulties are experienced' particularly in certain circumstances in joining the members of the connecter, such as the inconvenience of aligning the terminals with the openings when joining the members and the fact that with the members already joined the socket members cannot subsequently be threaded into a receiving socket without twisting the conductors connected to the plug member.

Other types of connecters have also been devis'ed in which the plug member is provided with g a central or axial post Ior making one of the contacts, and with a separatemember to one side of the axial member or entirely surrounding the axial member so that when this is inserted into the socket which has a corresponding central contactingmemberfor engaging the post and au annular side member for engaging the other conductor, it will not make any difference whether the parts are rotated to exactly the same point each time as before the plug is inserted, because the contacts will be properly made regardless of the relative rotary position of the plug with respect to the socket. It has also been discovered that by making the central opening in the socket larger at its outer end than at its inner end, it will be much easier to insert the central post into the socket in the proper manner.

However, in both of the two last mentioned means, the central opening in the socket has contained at least one electrical Contact which is alive at all times that the socket is in place, and has at all times another live contact exposed, so that if some metal object were accidentally dropped or pushed into the socket, a short circuit might very easily be caused and resultin the blowing out of fuses and other inconveniences, if not in fact in more serious consequences.

It is therefore one of the objects o1' this invention to provide an electrical connection of the type under discussion, in which the plug may be inserted into the socket in any relative rotary position desired, in which the aligning of the plug with respect to the socket is rendered as easy as possible, and in which there are no exposed contacts of the socket member which could -be short circuited by a metal member not made particularly to accomplish that purpose. Another object is to overcome the disadvantages previously 5 experienced in connection with the prior art devices.

Yet another object is to provide a socket member for an electrical connection, which socket member can be leftin the electrical circuit with- 10 out the plug inserted therein, without any fear that some foreign member might be accidentally inserted in thesocket and cause a short circuit.

Another object of this invention is to provide' a simplified and more eilicient form of electrical 15' connection of the type described.

The above and other objects will appear more clearly from the following detailedy description l when taken in connection with the accompanying drawings which illustrate by way of example one means for carrying out the objects of this invention. It is to be clearly understood that the following description and accompanying drawings are by way of illustration, and are not to be taken as in any way limiting the scope of this invention. The scope of this invention is to be limited only by the prior art and by the terms of the appended claims.

In the drawings:

Figure l is a sectional view of an electrical connecter selected for the purpose of illustration, showing the parts in their assembled relationship;

Figure 2 is a view illustrating a cross section of the socket member; 35

Figure 3 is a similar view illustrating a cross section of the plug member; and

Figure 4 is a similar sectional view showing the /t-himble or cap member used for concealing the electrical connections on the plug member.

Figures 5, 6 and 7 are views similar to Figure 1 showing modified forms of this invention.

Referring,- now more particularly to the drawings inV which similar numerals indicate corresponding parts, the numeral 1 indicates the in- 45 ner plug member which is formed from some insulating material such as hard rubber or other suitable compound. This plug member is formed with a frusto-conicalportion 2 having partially embedded in its outer apex portion a suitable 50 electrical contact post 3, the end of which projects outwardly, and terminates in a ball member l, or other suitable shape.

Adjacent the base of the frusto-conical portion, the plug member isy 'slotted as at 5` to re- 55 ceive the conical portion 2 of the plug I.

ceive an electrical contact ring E for the purpose of establishing the other electrical connection necessary in a device of this type. The annular member or ring 6 is arranged concentrically with respect to the contact post 3, so that all of its parts are equi-distant from the said -post. As shown in the drawings also, the post 3 projects outwardly a considerable distance further than the ring 6 for a purpose to be described hereinafter.

The base portion of the plug I is in the form of a cylinder threaded on its outside as shown at 1 in Figure 3. Two binding posts 8 and 8 respectively, or other suitable electrical connecting means are provided in the base of the plug. The binding post 8 as shown is connected by means such as the conductor I0 embedded in vthe plug member, with the contact post 3, and the binding post 9 is connected by a similar conductor II to the annular Contact ring 5. The lead wires from the electric iron or other electrical appliance to be connected, are connected preferably to the binding posts 8 and 9 respectively.

After the wires just mentioned have been connected to the binding posts, the thimble or cap member I2, having internal threads at I3 adapted to engage the threads 'I on the plug member I, is screwed in place to conceal the connection of the Wires from the attachment to the binding `posts 8 and 9 as just described. These wires pass out of the thimble. I2 through the opening I4 provided for this purpose.

Turning now to the socket member I5 as clearly set forth in Figure 2 of the drawings, it will be seen that this socket member is provided with an inner conical recess portion I6 adapted to re- AI: the base of this conical recess portion there is provided a cylindrical depression I1, in which is contained a U-shaped spring member I8 adapted to make contact with the post 3 and securely hold the portion 4 between the prongs I9 and 20. As will be distinctly noted in the drawings, this U-shaped contact member is secured in the recess I1 by means of the screw member 2l which passes through the opening 22 in the socket member. It is usually desirable to provide a washer member 23 underneath the head of the screw 2l as illustrated.

In position to receive the ring or annular member 6 of the plug, the socket I5 is provided with an annular recess 24, in which there is positioned a contact ring or annular member 25 for the purpose of making contact with the contact ring 6. The ring 25 is connected by means of a conductor 26 passing through the body of the socket member to a sleeve member 21 surrounding the outer portion of the socket member. As will be seen, this sleeve 21 is formed Iwith threads adapted to fit into the standard electric light socket having a threaded connection. As is well known, in this type of socket, the other contact member is in the bottom and center of the socket, in such position that when the member I5 is screwed into such a socket the sleeve 21 will form one of the contacts with the socket member, and the screw head 2 I will form the other contact.

It will be seen therefore that when the plug member I is inserted into the opening in the socket member I5, the portion 4 of the contact post 3 will be snapped between the prongs I9 and 20 of the U-shaped contact member I8 which will form an electrical connection between `the binding post 8 and the head of the screw 2|, and also firmly secure the plug member in place in the socket. At the same time that this electrical connection is formed, it will be seen that the ring member 6 will be received into the socket or recess portion 24 and will make contact with the ring 25, thereby forming a complete electrical connection between the binding post 9 and the threaded sleeve 21.

It will be appreciated that other wire attachingmeans than binding posts might be used in place of members 8 and 9. It is therefore to be understood that whenever the term binding post is mentioned in this specification or in the claims it is to be taken as including any equivalent structure for performing the same function.

In Figures 5, 6 and 7 of the drawings there are illustrated various modifications of this invention. In all of these figures for instance, the threaded sleeve 28, corresponding to the threaded sleeve 21 of Figures l and 2, is shown placed over a cylindrical portion 29 of the socket member 30, instead. of being placed over a threaded portion as in Figures 1 and 2. In order to secure the member 28 over the cylindrical portion 29, extensions 3| are formed at the outer end of the member 28 and are bent over the end of the cylindrical portion 29 and secured to the same by means of a screw 32 or similar suitable means.

In Figure 5 also there is illustrated a thimble 34 preferably made of metal which may be used instead of the thimble I2 shown in Figure 4.

'Ihis thimble 34, as shown, instead oi being threaded on to the base portion of the plug as illustrated in Figure l, may be secured thereto by means of a pair of screws 35. This construction has the advantage of being cheaper to make, and at the same time being less bulky than the thimble shown in Figure 4. It is formed with an opening 36 corresponding to the opening I4 in the thimble I2.

Also in Figure 5, the annular contact members have been made in the form of springs 31 and 38 having interengaging portions 39 and 40 whereby they may be positively held together.

In Figure 6, the annular contact members are shown in the form of solid rings 4I and 42, adapted to slide one inside the other when the two parts of the connecter are placed together. These rings are preferably formed one with a slightly recessed portion 43, and the other with a small tit 44 to engage in the recess.

Figure 7 shows the contact member in the socket portion of the connection as being a solid ring 45, whereas the contact member on the plug portion is made inthe form of a spring ring 46 which is adapted to resiliently engage the side of the solid ring 45 when the two members are brought together as above described. In order to facilitate the formation of the ring 45 with the bent over portions 41, it may be found desirable to make the portions 41 in the form of a plurality of separated tongues integrally formed with the'member 46. This will allow the nished member to have more springiness or resiliency so that it may more positively engage the ring 45.

It is to be noted in connection with the various forms set forth that the slot in which the annular member on the socket is positioned, is narrow enough so that the ball 4 on the end 'of the post 3 will not enter the same. but will slide over the same as it comes in Contact with it, and the process of inserting the plug in the socket will not be interfered with. It will also appear, that by the construction shown in Figure 2, it becomes impossible to bring the ball 4 in contact with the annular ring in the socket 25, and it is equally impossible to bring the annular ring 5 in contact with the spring clip member I8.

It will be seen also from the above that the arrangement of the contact members I8 and 25 in the socket member I5 is such that both of these members Iare recessed or countersunk into the member I5, in such a manner that a short circuit could not be formed unless a metal or other electrical conductor member were bentso as to t into both of the depressions at the same time. Obviously, a single foreign body thrust into the socket either by accident'or otherwise, could not form a short circuit as it might if the ring 25 for instance extended outside of the annular recess portion 24.

It will also be apparent that by virtue of thel conical shape of the portion I6 of the socket member, the contact post 4 which is the rst part of the plug member to enter the socket member, will be guided downwardly and enter the portion I5 with practically no expenditure of effort in aligning the terminals.

From the above description it will be perceived that a means has been provided for carrying out the objects of this invention in a very advantageous and desirable manner.

As pointed out above however, other forms and embodiments of my invention may -be availed of, and therefore it is to be distinctly understood that this invention is to be limited only by the prior art and by the terms of the appended claims.

` Having described my invention I claim:

1. In an electrical connection, a plug member of insulating material, concentric axial and annular contact members projecting therefrom in an axial direction, the axial ycontact member pro-' jecting farther than the annular member, a socket member of insulating material having an unobstructed socket formed therein, said socket ,being of gradually decreasing cross section from the outer toward the inner end thereof, the outer end of said socket being of greater diameter than the annular contact member projecting from said plug member, and the inner end of said socket merging with an axially extending axial recess formed at such inner end, said socket member having an annular groove formed in the wall of said socket and extending from such wall in a direction parallel to the axis of the plug, said groove being of a diameter to receive said annular contact member on the plug member but of such size as to exclude the axial contact member, an axial contact member disposed entirely within said axial recess and adapted to receive and make contact with said axial contact member on the plug member, and an annular contact member disposed entirely within said axially extending annular groove and adapted to receive and make contact with said annular contact member on the plug member.

2. In an electrical connection, a plug member of insulating material, concentric axial and annular contact members projectingtherefrom in an axial direction, the axial contact member projecting farther than the annular member, a socket member of insulating material having an unobstructed socket formed therein, said socket being of gradually decreasing cross section from the outer toward the inner end thereof, the outer end of said socket being of greater diameter than the annular contact member projecting from said plug member, andthe inner end of said socket merging with an axially extending axial recess formed at such inner end, said socket member having an annular groove formed in the wall of said socket and extending from such wall in a plug member, and said axial contact member on 

